pub fn dp_rec_mc(amount: u32) -> u32 {
    let money = vec![100,50,30,20,10,5,2,1];
    let mut rest = amount;
    let mut count = 0;
    for i in money{
        let num = rest / i;
        count += num;
        rest -= num * i;
        if rest == 0 {break;}
    }
    count
}
